The present invention relates generally to pet foods. More specifically, the present invention relates to pet foods that when chewed by pets, cause a mechanical, abrasive cleaning of the pets' teeth.
Many pets suffer from dental health problems. It is estimated that over 70% of dogs have some degree of gingival or periodontal disease. Plaque formation on the surface of the pets' teeth is a primary factor in the development of such problems. Dental plaque is a combination of bacteria, bacterial by-products which form a glycoprotein matrix, and salivary precipitates which bind to the tooth surface.
Contributing to the problem is the formation of tartar or dental calculus (mineralized plaque). Dental calculus forms on the tooth surface at or above the gum line and serves as a substrate for the additional accumulation of plaque. Apart from causing gum irritation and potentially, periodontal disease if left untreated, this calculus has an unsightly appearance.
Pets are more susceptible to the formation of plaque and calculus than animals in the wild. This is due to the nature of the foods that pets eat. In the wild, many animals eat foods that mechanically abrade plaque and calculus from the teeth. In contrast, pets are usually fed commercially available pet foods that although they may provide better nutritional value, do not in general subject the teeth to abrasive forces sufficient to clean the teeth. This is even true of dried kibbles that are able to abrade the teeth only to a very limited extent. In part, this is due to the fact that dried kibbles usually crumble when chewed by the pet.
Maintenance of optimal dental health depends on regular professional cleaning of all these accumulations both above and below the gum line, as well as adequate home care. Mechanical cleansing of the tooth surfaces with tooth brushing is an effective means of controlling the buildup of plaque and calculus in both humans and pets. However, most pet owners are reluctant or unable to provide the routine brushing necessary to maintain good oral health in their pets and would likely welcome an alternative provided by dietary means.
There have been various attempts to provide products for improving pet dental health. One such attempt centers around the use of chews made from rawhide or rawhide substitutes. By allowing the pet to gnaw or chew on such rawhide products, the pet abrades calculus and plaque from its teeth. It is also possible, as described in European patent application 0272968, to incorporate various oral care agents into such chews. These products, however, have the drawback that they are typically expensive. Moreover, they are usually only effective with dogs that are prone to chew and gnaw.
Another approach has been to incorporate oral care agents into certain pet foods. For example, U.S. Pat. No. 5,000,940 discloses baked dog biscuits which contain a tetrasodium pyrophosphate salt. The patent states that the salt causes a reduction in calculus accumulation. Another example of such an approach is, European patent application 0205354 which discloses baked dog biscuits which contain vegetable fibers to abrade the teeth of the dog when chewed. A drawback with both of these products, however, is that the biscuits crumble upon being bitten. Hence, the dog cannot chew the product and little abrasion occurs. This thereby reduces the efficacy of the product.
A further approach is described in U.S. Pat. No. 5,431,927. That patent describes a dried product which contains aligned fibers which, when chewed, fracture in long striations rather than crumbling. The patent states that this allows the product to remain in contact with the animals' teeth for a longer period of time hence enhancing the abrasive effect. However, a disadvantage of this product is that it must be produced using a specially coated die that allows laminar flow conditions within the die. The laminar flow condition is reported to cause the alignment of the fibers within the product leading to the fracturing of the product when bitten by the animal. The use of such dies necessitates a complicated procedure for manufacturing the product.
There is therefore a need for an improved dental care pet food.